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<title>CodeMirror: Mode-Changing Demo</title>
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<article>
<h2>Mode-Changing Demo</h2>
<form><textarea id="code" name="code">
;; If there is Scheme code in here, the editor will be in Scheme mode.
;; If you put in JS instead, it'll switch to JS mode.

(define (double x)
  (* x x))
</textarea></form>

<p>On changes to the content of the above editor, a (crude) script
tries to auto-detect the language used, and switches the editor to
either JavaScript or Scheme mode based on that.</p>

<script>
  var editor = CodeMirror.fromTextArea(document.getElementById("code"), {
    mode: "scheme",
    lineNumbers: true
  });
  var pending;
  editor.on("change", function() {
    clearTimeout(pending);
    pending = setTimeout(update, 400);
  });
  function looksLikeScheme(code) {
    return !/^\s*\(\s*function\b/.test(code) && /^\s*[;\(]/.test(code);
  }
  function update() {
    editor.setOption("mode", looksLikeScheme(editor.getValue()) ? "scheme" : "javascript");
  }
</script>
  </article>
